1. Field of the Invention
The invention relates to a process for demulsifying oil/water emulsions, e.g. of exhausted cooling lubricant, deep drawing, cutting and/or drilling emulsions by using organic demulsifiers and the use of said process.
In the operations of working and machining metallic materials it is frequently necessary to employ oil-in-water emulsions. These emulsions are used for cooling the workpieces and tools in machining, e.g. in cutting, drilling and turning. In the non-cutting operations of metal working, e.g. in deep-drawing, said emulsions act as lubricants and release agents.
The oil phase of such emulsions predominantly consists of natural or synthetic oils of various chemical composition and origin, while the oil and water phases comprise emulsifiers, wetting agents and other auxiliary materials. The term "emulsions" as employed herein is intended also to include the classic alkaline, neutral, or acidic degreasing and cleansing baths contaminated by an oil content.
Such emulsions are subject to deterioration and exhaustion during use and, thus, have to be continuously or discontinuously disposed of. The most important step in the disposal of such exhausted emulsions is the demulsification thereof. That is, the oil content thereof must be separated as much as possible from the demulsified aqueous phase so that the latter, subsequently to a pertinent after-treatment, may be discharged into a sewage system or drainage ditch without giving rise to ecological problems.